diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6f32091ed3..a34e7bd401 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ Bugfixes:
 - Proxying certain `[Serializable]` classes produces proxy types that fail PEVerify test (@stakx, #367)
 - `private protected` methods are not intercepted (@CrispyDrone, #535)
 - `System.UIntPtr` unsupported (@stakx, #546)
+- DynamicProxy generates two modules when proceeding from a class proxy's protected method to the target, causing an `InvalidOperationException` when saving the generated assembly to disk (@stakx, #569)
 
 Deprecations:
  - Removed support for the .NET Framework < 4.5 and .NET Standard 1.x. (@stakx, #495, #496)
diff --git a/src/Castle.Core.Tests.WeakNamed/DynamicProxy.Tests/ClassProxyWithTargetTestCase.cs b/src/Castle.Core.Tests.WeakNamed/DynamicProxy.Tests/ClassProxyWithTargetTestCase.cs
new file mode 100644
index 0000000000..2d4f8d3fb8
--- /dev/null
+++ b/src/Castle.Core.Tests.WeakNamed/DynamicProxy.Tests/ClassProxyWithTargetTestCase.cs
@@ -0,0 +1,42 @@
+// Copyright 2004-2021 Castle Project - http://www.castleproject.org/
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+namespace Castle.DynamicProxy.Tests
+{
+	using NUnit.Framework;
+
+	[TestFixture]
+	public class ClassProxyWithTargetTestCase : BasePEVerifyTestCase
+	{
+		[Test]
+		public void Forwards_to_protected_method()
+		{
+			var proxy = generator.CreateClassProxyWithTarget(new ClassWithProtectedMethod());
+			Assert.AreEqual(42, proxy.InvokeFortyTwo());
+		}
+
+		public class ClassWithProtectedMethod
+		{
+			public int InvokeFortyTwo()
+			{
+				return FortyTwo();
+			}
+
+			protected virtual int FortyTwo()
+			{
+				return 42;
+			}
+		}
+	}
+}
diff --git a/src/Castle.Core/DynamicProxy/Generators/DelegateTypeGenerator.cs b/src/Castle.Core/DynamicProxy/Generators/DelegateTypeGenerator.cs
index 11db73f2ac..8efd6d40cf 100644
--- a/src/Castle.Core/DynamicProxy/Generators/DelegateTypeGenerator.cs
+++ b/src/Castle.Core/DynamicProxy/Generators/DelegateTypeGenerator.cs
@@ -78,7 +78,8 @@ private AbstractTypeEmitter GetEmitter(ClassEmitter @class, INamingScope namingS
 			                                 uniqueName,
 			                                 typeof(MulticastDelegate),
 			                                 Type.EmptyTypes,
-			                                 DelegateFlags);
+			                                 DelegateFlags,
+			                                 forceUnsigned: @class.InStrongNamedModule == false);
 			@delegate.CopyGenericParametersFromMethod(method.Method);
 			return @delegate;
 		}
diff --git a/src/Castle.Core/DynamicProxy/Generators/Emitters/ClassEmitter.cs b/src/Castle.Core/DynamicProxy/Generators/Emitters/ClassEmitter.cs
index 4a428c8880..cb2023bc87 100644
--- a/src/Castle.Core/DynamicProxy/Generators/Emitters/ClassEmitter.cs
+++ b/src/Castle.Core/DynamicProxy/Generators/Emitters/ClassEmitter.cs
@@ -34,12 +34,6 @@ public ClassEmitter(ModuleScope modulescope, string name, Type baseType, IEnumer
 		{
 		}
 
-		public ClassEmitter(ModuleScope modulescope, string name, Type baseType, IEnumerable<Type> interfaces,
-		                    TypeAttributes flags)
-			: this(modulescope, name, baseType, interfaces, flags, forceUnsigned: false)
-		{
-		}
-
 		public ClassEmitter(ModuleScope modulescope, string name, Type baseType, IEnumerable<Type> interfaces,
 		                    TypeAttributes flags,
 		                    bool forceUnsigned)